According to a 2009 estimate by the U.S. Society of Civil Engineers, more than one in four U.S. bridges are either structurally deficient or functionally obsolete. While newer “smart” bridges have embedded wired networks of sensors to monitor their structural integrity, the high cost of installing such systems on existing bridges is simply unaffordable for strained city, state and federal budgets. Now University of Maryland electrical engineering researcher Mehdi Kalantari has developed a tiny wireless sensor that monitors and transmits minute-by-minute data on a bridge’s structural integrity that he estimates is one-hundredth the cost of a wired network approach.